Method for producing a component from steel by hot forming

Patent metadata

Field	Value
Publication number	US-10246758-B2
Application number	US-201314389072-A
Country	US
Kind code	B2
Filing date	Feb 27, 2013
Priority date	Mar 30, 2012
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

The invention relates to a method for producing a component from transformable steel by hot forming, in which a plate first is cut out of a strip or sheet as the pre-material, and is then heated to forming temperature and pre-formed, having an at least partially martensitic transformation structure after forming. Instead of a press mold hardening, the at least partially martensitic transformation structure is created in the pre-material, or in the plate to be formed, by austenitization and quenching already before forming, and then the thus-conditioned plate is reheated after forming, while maintaining the at least partially martensitic transformation structure, to a temperature below the Ac1 transformation temperature, and formed at this temperature.

First claim

The invention claimed is:

1. A method for the production of a component from transformable steel, comprising the steps in the order of:
cutting to size a blank as source material from a strip or metal sheet;
austenitizing and quenching the blank such as to produce a partly martensitic transformation microstructure and a residual austenite microstructure, by heating the blank to an austenitizing temperature within a continuous annealing process and subsequently quenching the blank;
applying a coating on the blank by a hot dip process after the annealing process;
reheating the blank to a forming temperature below the Ac 1 transformation temperature, while maintaining the partly martensitic transformation microstructure and the residual austenite microstructure; and
forming the blank at the forming temperature below the Ac 1 transformation temperature into the component while still maintaining the partly martensitic transformation microstructure and the residual austenite microstructure in the component.

2. The method of claim 1 , further comprising tempering the blank after undergoing quenching.

3. The method of claim 2 , wherein the blank is tempered at a temperature range of 250° C. to 680° C.

4. The method of claim 3 , wherein the blank is tempered at a temperature range of 430° C. to 490° C.

5. The method of claim 1 , further comprising tempering the blank prior to applying the coating.

6. The method of claim 5 , wherein the blank is tempered at a temperature range of 250° C. to 680° C.

7. The method of claim 6 , wherein the blank is tempered at a temperature range of 430° C. to 490° C.

8. The method of claim 5 , wherein the blank is tempered at a tempering temperature which corresponds to a melt bath temperature.

9. The method of claim 1 , further comprising tempering the blank after applying the coating.

10. The method of claim 9 , wherein the blank is tempered at a temperature range of 250° C. to 680° C.

11. The method of claim 10 , wherein the blank is tempered at a temperature range of 430° C. to 490° C.

12. The method of claim 9 , wherein the blank is tempered at a tempering temperature which corresponds to a melt bath temperature.

13. The method of claim 1 , wherein the blank is formed at a temperature below 700° C.

14. The method of claim 1 , wherein the blank is formed at a temperature range between 400° C. and 700° C.

15. The method of claim 1 , wherein the blank is formed at a temperature range between 460° C. and 700° C.

16. The method of claim 1 , wherein the metallic coating is made of at least one element selected from the group consisting of Zn, Mg, Al, and Si, and an alloy system of the afore-mentioned elements.

17. The method of claim 1 , wherein the blank is heated inductively, conductively or by irradiation.

18. The method of claim 1 , wherein that the blank is a hot or cold rolled steel strip.

Assignees

• Salzgitter Flachstahl Gmbh

Inventors

• Luther Friedrich
• Evertz Thomas
• Muetze Stefan
• Braun Michael

Classifications

• C21D2211/001

  Austenite · CPC title

• C23C2/12

  Aluminium or alloys based thereon · CPC title

• C21D8/0236

  Cold rolling · CPC title

• C21D1/42

  Induction heating · CPC title

• C21D8/0263

  following hot rolling · CPC title